Addition agents and mineral oil lubricant compositions containing the same



v Patented July 15, 1952 THE SAME Herschel o. Smith, Wallingf ord, and

Cantrell, Lansdowne, Pa., assignors toGuJfOiI Corporation,. Pittsburgh,Pa.,.

' Pennsylvania a corporation of vNo'Drawing. Applicationdanuany 511949,7

Serial No. 73,218

This inventionrelates toaddition agents and mineraloil lubricantcompositions'containing the same andymore" particularly; it-isconcernedwith improvement agentswhich'confer improved-antioxidant;"corrosioninhibiting and detergency properties on mineral oil lubricants.

It is recognized in the art'that mineral oil lubricantsarereadilyoxidized underservice conditions thereby reducing the service life ofinterna'l combustion engines and steam' turbines. A concomitant effectis" corrosion of bearing surfaces. These problem's'become particularlyacute when a highly refined para'flinic' base mineral oili'siemployeda's'thelubricant;

' In thelubrication 'of 'internalcombustion enginesof all types,-particularly when severe op- ..erating conditions"are'enc'ountered;mineral lubricating;oils"frequentlyproveunsatisfactory because theytend" to' depositvarnish, gum" and sludge on' the engine surfaces; suchas the cylin defwall's, pistons and ring's and" also" to inducecorrosion 'of bearing materials" thereby causing failure of the engine:These'problemshave'become"; increasingly serious because'of the trendtowaril" higher efficiency or higher" power output peri'unit'weight-of"engineywhich"results in conditions'tendingtoacceleratethe'deteriorating in fluencesf on the mineral" oil' lubricant;The fori'nation arise-called varnishes and "sludges on" engir'i'esurfaces is a" result of oxidation" efie'ctson the lubricatingioils.'I'hepre'senceof gums, var= nishes and 'slud'ges'is detrimentalformanyreasons.- "These substances ten'd'to increase *rin'g stickingandaccelerate the" formation of further deposits on piston surfaces and infixed" parts or thecombustion chamber. Thesludgesformed iii'thecrankcase Ofthe' engine increase the rate of" corrosion-of bearingsurfaces, especiallvof bearing'alloys-offthe types now'inuse;

steam" 'tu'rbines;,. the" corrosion problem" is particularly acutebecauseof" the" presence of watefim the mineral" on "lubricant" and inaddi= tion to hearing corrosion, rusting? may also" be encountered. V j

- Itis an object of" this; invention, therefore" to prepare animprovement agent'which' will obviate the oxidation andcorrosiondiflicultiesi encountered in the use" of'mineral oillubricants;

It is -a further object of this invention. toiiprovideumprovedmineral'oil' lubricant composi= tions which are stable" in storageanduse and" in which oxidationandcorrosioni effects are" mate'-riallyinhibited.

' In our copending=- application Serial No. 718;- 902; "filed December27; i946,- there isdisclosed and claimed an addition agent for' mineraloil lubricants which coi'ifersexcellent anti oxidant, corrosioninhibitingandpressuracarrying properties -on'mineral oil lubricants.Such improve mentfagent is preparcd by heating an essentially Iprovem'ent agentfor mineraloil lubricants which is prepared by-h'eatingan essentially p'araffin'icbase lubricating-oil with phosphoruspentasulfide-in thepresence of a surface active silica-contai'ningfsolid catalyst, It is shown in'that patent that when phosphoruspentasulfide is reacted withan essentially-paraflinic base lubricatingoil in the presence of a surfaceactive silica-containing 'so'lidcatalyst, the prior aluminum chloride treatment of the lubricating oilas'disclosed' in our application Serial No. 718.902 may? be omitted; Itis" also shown in our patent that when the prior aluminum chloridetreatment o f' t'he arafiinic base lubricating oil is combined with 1reaction of the aluminum chloride treated prod l h phosphoruspentasulfidein the presence of' a surface active "silica-containin'gcatalyst.

lighter coloredv products are obtained.

The" objects of the present invention are'.*ac'- complishedby.providingv improvement agents for mineralfioil, lubricants by reactingan essentially paraffinicba'se lubricating oil or the aluminum chloridetreated product thereofwith phosphorus penta'sulfidethroughthe useflofany. of the mefth-f I ods disclosedin ourlcopending application SerialNo. '7l8;9o2 and'our PatentNo. 2.456;:336 andwith analkylorthophosphate' having at least 5 carbon atoms in" the alkyl group.Such improvement agents;'asfwellas the mineral oil lubricantcc'im--positions containing them, are" believed to be novel and are; consideredparts of our invention.

The present invention maybe regarded asan improvementoverthe inventionsdisclosed in our above-identified copending' application and pat ent;While the additionfagents disclosed therein confer excellentantioxidant}corrosion-inhibiting and pressure car'rying properties onmineral oil lubricants, they sometimes failto pass the well knownCopper'Strip Test (Meth0d-5 30.31, Fed- Mal-Specification VV-L-'791c,May 12,1945, page 259) thus indicating the presence of elementary sulfuror the so-called corrosive sulfur. While We-id0-'IlOt.-WiSh"t0 be boundby any theory astto the exact-nature of the-phosphoruspentasullidereaction-products with anessentially. paraifinic base lubri'catingoil,.it is our present belief that either elementary sulfur orincompletelybound sulfur or both; are formed in the reaction; I I :Inaccordance with: the present; invention,:such elementary';or'aincompletely' bound sulfur is: non

tralizedi or -acc'e'pte by gcombination' witlithe 2,603,602 STATESPATENT OFF-VICE,

It is still necessary for the purposes of the 7 present invention toemploy an essentially paraff finic base lubricating oil as theinitialmaterial,- because other hydrocarbon materials produce a black,sludge-like, difiicultly soluble product regardless'of whether the prior"aluminum'chloride treatment or reaction in the presence of 'a' surfaceactive silica-containing solid" catalyst are employed. The reasons forthe advantageous effects of the prior aluminum chloride treatment or ofthe surface active silica-containing-solid catalyst on the reaction whenan essentially paraffinic base lubricating oil is employed are not fullyunderstood. However, the use of atleast one of these methods isessentialfor the practice of. ouninve'ntion'since, the prior aluminumchloride treatment or the use of a surface active silica-containingcatalyst is omitted, the advan tageous results of our invention are notobtained. In order to obtain the results of our invention, therefore, it'is necessary (1) to employ an es-. sentiallyparafiinic base lubricatingoil, and 2) to' conduct'the reaction of the oil and alkylorthophosphatewith phosphorus 'pentasulfide only afteraluminum chloride hasjbeenreacted with the oil and/or the reaction with phosphorus pentasulfidelisconducted in'the presence of. a surface activeSiliOflrCOIltfiiIliDQSOlid catalyst. Theessentially paraffinic baselubricating oil used as a starting m'aterial'in accordance with ourinvention 'may be derived from any paraffinic crude,.such asPennsylvania, Mid-conti nent, or other parafiinic base crudes. Thelubri: ca'ting' oil rnanufactured from such crudes in ac'cordance withconventional methods and may loci-refined in accordance with methodsknown in the art If 'itis desired to treat the essentially parafiinicbase lubricating oil with aluminum chloride, such treatmentisaccomplished as, described in four copending application Serial No.718,902. Briefly, such treatment comprises heating the essentiallyparaflinic base lubricating oil with from 1 to 20 per cent by weightofanhydrous alur'riinumchloride at a temperature of from 15.0?to-1300'iv F. while the mixtureis vigorously agitatedl' fThetir'ne oftreatment mayvary in accordance 'with the amount of aluminum chlorideused and the temperature'of'treatment, longer times being required withless aluminum chloride and lower temperatures' In general," thetreatment will be completed after four,or five hours. After, thetreatment is completed, agita tion is stopped'and the sludge containingmost of the'aluminum chloride settles out from the main body of the oiland is drawn 0111' The supernatant body of the treated oil may containfurthergquantities of aluminum chloride'finely dispersed therethrough,andin order to insure the removalof all aluminum chloride from thetreated oil, agitation with an adsorbent clay followed by filtrationmaybe employed. At the higher temperatures of treatment with aluminumchloride some conversion of the paraflinic base oil to lower boilingproducts may take place. Althoughsuch conversion is slight, the productmayLbetOpped if desired; that is, distilled to TB! move the lowerboiling products overhead and to recover .as' a residue the bulk ofthe'aluminum chloride treated oil having a minimum initial boiling pointin the range 490 to 530 F.

The essentially parafiinic base lubricating .oil treated with aluminum;chloride as disclosed hereinabove may then bereacted with the alkyltinsel-era and t horus' pentasulfide. This may be accomplished either byreacting I with phosphorus pentasulfide per se, as disclosed in ourcopending application Serial No. 718,902,

orin the presenceiof a surface active silica-containing' solid catalystas disclosed in our Patent No. 2,456,336; i v

If it is desired "to react the aluminum chloride treated oil and-thealkyl orthophosphate with phosphorus penta'sulfide per se, this reactionis accomplished by'a'dding from 2 to 20 per cent by -we ight of P2355011the mixture of oil and alkyl orthophosphate, preferably 5 to 10 percent, and heating with agitation at a minimum reaction temperature of450 F. and a maximum reaction temperature below the temperature wherecracking of the oil begins. Hydrogen sulfide isievolved and when theevolution of hydrogen sulfide has nearly ceased, the temperature ofYthereaction mixture may be increased within. the maximum temperaturedisclosed above, saytd about'500 F. for thecompletion of the reaction.

If desired; the aluminum chloride treated parafiini'c base lubricatingoil and the alkyl orthophosphate may be reacted with phosphoruspentasulfide in" the presence of a surface active silica-containingsolid catalyst; or, the prior aluminum chloride treatment may be omittedand the essential parafiinic base lubricating oil and alkylorthophosphate maybe 'reactedwith phosphorus pentasulfideinthe presenceof a surface active silica-containing solid catalyst. The re'actionofthe essentially parafiinic base 1ubri-' catingoil and alkylorthophosphate, whether or not pretreated with aluminum chloride, withphosphorus pentas'ulfide in the presence of a surface activesilica-containing solid catalyst is accomplished by adding 2 to 20 percent by weight of P285, preferably from 5 to 10 per cent, to the mixtureof essentially paraffinic" base lubricating oil and alkyl orthophosphateand heating with agitation at atemperature in'the range from 300 F. to:a maximum temperature below 'theltern-l perature where cracking of theoil, that is, pyro-T lytic decomposition of the oil, begins. Generallythe minimum cracking temperature of theoil variesbe'tween 490 to 530?F., depending upon the particular oil used. The surface active silicacontaining solid catalyst is employed in amounts of from 2 to' 25 percent by' weight'of the reaction mixture charged and preferably in anamount of lopercent byweight. Larger amounts than 10 percent areordinarily not necessary; but larger amounts will produce a producthaving .allghter color. During-the course. of the reaction hydrogensulfide is evolved and the phosphorus and sulfur become incorporated-inthe reaction product. When the evolution of hydrogen sulfidehas nearlyceased, the temperature of thereac'tion mixture may be increased withinthe maximum temperature mentioned above, say to about 500? F.. forcompletion o1? the. reaction. The mixture is then'filtered to removethe-catalyst. t t The surface -active silicaecontaining solid catalystsmay comprise'activated clays, silicaalumina cracking catalysts and thelike. Thus, activated clays, that mammal clays such; as bentonite,smectite, fluoridin, fullers earth and the like which have beentreatedwith acid, such as aredescribed in U. S. Patent No. 1,898,165,for example, may be advantageously employed. Synthetic silica-alumina.catalysts'of the type used for the crackin ofqhydrocarbon oils, ex-

' ,a'mples-ofwhich are described. in U. S. Patent No.

207 4945 nd. U.-. s. Pa -N0. 2,283,173, mayalso be employed. Activatedsilica gel is also suitable. Asmay be seen, the term surface activesilicacontaining solid catalyst comprises a wide variety ofmaterials,the predominant characteristic of .which is the presence of silica in asurface active, thatis, activated form. r I r In accordance with thepresent invention, analkyl orthophosphate is admixed withthee'ssentially parafiinic base lubricating oiland the mixture reacted withphosphorus pentasulfide as disclosed hereinaboveyor thealkylorthophosphate maybe added to the mixture of the phosphorus pentasulfideand the essentially paraffinic base lubricating oil during thereactionafter the evolutionof hydrogen. sulfidehas substantially ceased, but;prior. to; completion of the. reaction. The alkyl: orthophosphate'isvordinarily added in proe portionsrrangingirom to '75 per cent byweightvof its mixture with the parafiinic base lubricating oil, sufficient toremove free or corrosive sulfur in the phosphorus pentasulfide reactionproduct. Ordinarily not more than 50 per cent of the alkylorthophosphate is sufficient for most purposes.

The alkyl orthophosphate with which this invention is concerned may bemono-, di-, or trialkyl esters of orthophosphoric acid having thefollowing general formulas: 3

wherein R represents a saturated aliphatic hydrocarbon radical of atleast 5 carbon atoms, preferably from 8 to 18 carbon atoms. The-upperlimit of 18 ;carbo,n atoms is 'noticritical, it being dictated byconsiderations of commercial avail:

While any of the esters mentioned above may be used, we .preferto-usetrialkylphosphates and, of these, trioctyl phosphate." In view ofthefact that these esters of phosphoric acid are commercially available,methodsfor their preparation need not be described here.

' 'Ifhefollowing examples illustrate the preparation of our newimprovement agents. 7

Example I.-In,the presence of 5 per cent by weight of;- an activatedclay catalyst (Filtrol),

50;: parts by weightiof tri-s ec octyl phosphateand50 parts by weightofan SAE 30 Mid-Continent paraffinic base lubricating oil were treatedwith 10 per cent by weight of phosphorus pentasulfide by agitating for 1hour while raisingthe temperature to 490 F., and agitating at thattemperature for two hours or until the evolution.

ofi hydrogen sulfide subside'df Then; the tem'- perature was raised-to520= where "it was held fon-6 hours with continuecl -agitatiorr of "thereactants.- Tha mixture was ,thencooled: and: filtered. I, The.properties; of this product were; as; iollowsz; a q: J Gravity,- 1 114-;r 113.2 o horu i e en ome pg c n .1 Neutralization No. C0101; 1

Example, IL- An; additive was prepared insaccordancewiththe procedure ofExample. I, in, which 5 parts. by weight of tri-Sec octyl. phosphateand, 25 parts by weight: of an SAE'30 par-aflinic; baseI lubricating oilwere reacted withl2 parts,.-by. weightv of phosphorus pentasulfidein thepresence of 10 per cent byweightoiFiltrol, The; additive so preparedhad'the followingprop erties:

Gravity, API

Color, NPA. 2.25 .Sulfur, percent 3.2 Phosphorus, per cent 3.0Neutralization No. 14.0

Erample III.Into a reactionjvesseLjthere were placed parts by weight ofan essentially parafiinic base lubricating oil which hadbelen treatedwith aluminum chloride in accordance with v;copending application SerialNo. 718,902 and 50 parts by weight of tri-sec octyl phosphate. To thismixture were added.l2.5 partsby weight of phosphorus pentasulfide. Themixture was agitated and the temperature raised to 490 F; during thecourse of 1 hour. It was held at that temperature for 2 hours and thenraised to .520 where .it washeldr for 6'hours. The mixture wasvthencooled and .had they following properties:. g I

Gravity, API 14.2 Phosphorus, per cent 3.0 Sulfur, per cent 3.2Neutralization No. 6.0 Color, NPA 4.5

l "Gravity, API .4 14.1

Phosphorus, per cent 2.4 Sulfur, percent i 2.6 Neutralization No. 11.0Color,,,NPA- 4.5

The reaction' products' obtained in accordance with the precedingexamples are excellent improvement agents for mineral oil lubricantcompositions. They are light colored and readily soluble in all types ofmineral oils, that is paraffinic, naphthenic or mixed base mineral oilsand, as a matter of fact, can be blended with mineral oils inproportions as high as 50 per cent by weight or higher. This excellentsolubilityof our new improvement agents enables the preparation ofconcentrated solutions, which may then be diluted down to the proportiondesired in the final mineral oil lubricant composition. As stated, ournew improvement agents confer excellent anti-oxidant andcorrosion-inhibiting-properties f on the mineral lubricating oils withwhich they are incorporated, and-are characterized by a high degree ofpotency at high temperatures. For these purposes, our new improvementagents are generally added to mineral oils in minor amounts, say from0.1 to 20 per cent by weight of mineral oil, sufiicient to conferimproved antioxidant and corrosion-inhibiting properties on the minerallubricating oils with which they are incorporated. Lubricating oilscontaining our new improvement, agents successfully pass the CopperStrip Test.

The following examples illustrate the use of our new improvement agentsto obtain improved mineral oil lubricant compositions.

Example 'V.-A motor oil was prepared by treating a-solvent refined SAE30 motor oil with 1 per cent of the additive prepared in accordance withthe procedure of Example I. The following is a summary of the testvalues in comparison with that of the untreated oil:

Unimproved Improved Motor Oil Motor Oil Gravity: API 29.0 28.9Viscosity, SUV 549 661 Color, NPA 4. 4. 25 Oxidation and B CorrosionTest Method 257, Gulf: I 7

Duration of Test: hr '48 48 Oil Bath Temper'aturezPF 347 347 Air Rate:cc./hr 2,000 2,000 Quantity of Oil: cc. 300 Bearing Type Cd-Ag CdAgWt.-Change: Grams. -0. 2040 +0. 0018 Wt. Change: Percent. 0. 93 +0.01Copper StripTesL, Passes Passes In order to determine'the comparativeimprovement in properties obtained by using the additive of the presentinvention, additives prepared in accordance with the disclosures ofSerial No.

Unimproved Motor Improved Motor Oil Oil Gravity: API 29.0 29.1Viscosity, SUV: 100 F 521 520 -Color, NBA 1. 1.75

Oxidation and Bearing Corrosion Test Method 257, Gulf: 1 I

7 Duration of Test: hrs r 48 48 vOil Bath Temperature: F. 347 347 AirRate: cc./hr 2,000 2, 000 Quantity of Oil: cc. 300 300 Bearing TypeOd-Ag Cu-Pb Cd-Ag Cu-Pb Wt. Change: Grams" -0. 1744 0. 0133 0.048 0.0018 Wt. Change: Percent. 0. 96 0.08 0. 01 0. 01 Copper Strip TestPasses Passes Example VI .An SAE 30 motor oil was treated with l'percent of the additive prepared in accordance with the procedure ofExample II. Comparison of the tests of the treated oil and untreated oilare:

718,902, Patent No. 2,456,336 and the present invention were subjectedto the well known Falex Wear Test and the Copper Strip Test. In eachinstance 2 parts by weight of the additive were compounded with 98 partsby weight of a highly Example VII .An SAE 30 motor oil was treated with1 per cent of the additive prepared in acrefined motor oil. Theuncompounded oil is included for purposes of comparison.

Uncom- Lubricant Lubricant Lubricant pounded of S. .N. 01' Pat. ofPresen Lubricant 718,902 2,456,336 Invention Gravity: API 29.3

Viscosity, SUV: 100 F 246 242 34 ((llgigglslzggi zgtflu- P 1'. 75 T 1.75 1. 75 1. 75 asses Fallex Wear Test 1000 lb. Gaug wished TamlshedPasses 5 min:

Wear: No. 01' Teeth Fails 5 Gauge Load at Seizure: Lb.-- 1, 753' l, 7582, 508

cordance with the procedure of Example: IV. Comparison of the tests ofthe treated and untreated motor oil are:

F'rqm the above table. it isobvious that not only do'the additives of-the present invention confer enhanced pressure carrying properties, butlubri Bi .cantscontairnng' them passthe Copper Strip Test. The Oxidationand Bearing Corrosion.= -Test,

Method :25'7?,:Gulf*referred to inithe foregoing .ex-

it "is advantageous to employ commercial bearing.

shells. 1 These shells comprise a' suitable-metal backing faced with thealloy bearing metal. In this Way the actual bearing face is subjected tosevere deterioration conditions. By comparison of the results of suchtests with actual service tests, we have found them to be in substantialagreement as to the suitability of particular lubricants.

As shown in the above examples, the addition of our new improvementagents to mineral oil lubricant compositions confers excellentantioxidant, corrosion-inhibiting and pressure carrying properties. Atthe same time the compositions so obtained are stable in storage and useand have a color which is substantially unaffected by the addition ofthe improvement agent. The lubricants obtained pass the Copper StripTest..

While we have shown in the examples the preparation of compoundedlubricating oils, our invention is not limited thereto but comprises allmineral oil lubricant compositions containing our new improvementagents, such as greases and the like. Furthermore, conventional additionagents such as viscosity index improvers, pour point depressants,anti-foam agents and the like may be added without departing from thespirit of the invention.

Resort may be had to such modification and variations as fall within thespirit of the invention and the scope of the appended claims.

We claim:

1. The process of preparing an improvement agent for mineral oillubricants which comprises heating an essentially paraffinic baselubricating oil with anhydrous aluminum chloride at a temperature offrom 150 to 300 F., removing aluminum chloride from the reactionproduct, and reacting said product and from 10 to '75 per cent by weightof an alkyl phosphate having at least 5 carbon atoms in the alkyl groupwith phosphorus pentasulfide at an elevated temperature not below 300 F.and not in excess of the minimum cracking temperature of said product toincorporate phosphorus and sulfur therein.

2. The process of preparing an improvement agent for mineral oillubricants which comprises heating an essentially paraiiinic baselubricating oil with anhydrous aluminum chloride at a temperature offrom 150 to 300 removing aluminum chloride from the reaction product,and reacting said product and from to '75 per cent by weight of an alkylphosphate having at least 5 carbon atoms in the alkyl group withphosphorus pentasulfide at a temperature of from 450 F. to a maximumtemperature below the minimum cracking. temperature of said product toincorporate phosphorus and sulfur therein. 3. The process of preparingan improvement agent for mineral oil lubricants which comprises h atinan s nt l a af e u r a oilgwithfrom 1,.to 20;,per; cent by weight -ofanhydrous 1 aluminum chloride at. a I temperature I f m 5 L-r o-3'00?Fsxremov l m n m' chloride. from the reaction product; andvreact ingsaid product and from 10 to '75 percent by wei ht o aa alkyl ph p a rms:at l a ;5,;car bei i atoms; in the alkyl group with from 2 .20; n rwent: b I e t ofgphospborus e as fide=- at-eztem r o omem t0. maximum--temperature belowthe mm'mum cracking temperature of said production-in:corporate ;.,phosphorus and. sulfur-therein r; l.-.The process of claim,3, wherein1-the product is; dissolved :in armineral lubricating oil,5-.The process of claim Bywherein; theqalkyl phosphate contains from 8to 18 carbon atoms inan alkyl group.

6. The process of claim 5, wherein the alkyl ester of phosphoric acid istri-sec octyl phosphate.

'7. The process of preparing an improvement agent for mineral oillubricants which comprises heating an essentially paraffinic baselubricating oil, phosphorus pentasulfide and from 10 to '75 per cent byweight of an alkyl orthophosphate having from 3 to 18 carbon atoms in analkyl group, in the presence of a surface active silicacontaining solidcatalyst and at a temperature of from 300 F. to a maximum temperaturebelow the minimum cracking temperature of said lubricating oil toincorporate phosphorus and sulfur therein.

B. The process of preparing an improvement agent for mineral oillubricants which comprises heating an essentially paraffinic baselubricating oil, from 2 to 20 per cent by weight of phosphoruspentasulfide, and from 10 to 50 per cent by weight of an alkylorthophosphate having from 8 to 18 carbon atoms in an alkyl group, inthe presence of from 2 to 25 per cent by Weight of a surface activesilica-containing solid catalyst and at a temperature of from 300 F. toa maximum temperature below the minimum cracking temperature of said oilto incorporate phosphorus and sulfur therein.

9. The process of claim 8 wherein the alkyl orthophosphate is tri-secoctyl phosphate.

10. The process of preparing an improvement agent for mineral oillubricants which comprises heating an essentially parafiinic baselubricating oil with from 1 to 20 per cent by weight of anhydrousaluminum chloride at a temperature of from 150 to 300 F., removingaluminum chloride from the reaction product, heating said product withfrom 2 to 20 per cent by weight of phosphorus pentasulfide in thepresence of a surface active silica-contained solid catalyst and from 10to 75 per cent by weight of an alkyl orthophosphate having from 8 to 18carbon atoms in an alkyl group at a temperature of from 300 F. to amaximum temperature below the minimum cracking temperature of thealuminum chloride treated oil 14. The product obtainable by the processof claim 7.

15. The product obtainable by the process of claim 10. 7 16. A lubricantcomposition comprising a major amount of a mineral lubricating oil and aminor amount,;sufficient to confer improved'antioxidant andcorrosion-inhibiting properties on the'composition, of the productobtainable by the process of claim 1. g I e '17. A lubricant compositioncomprising a major amount of a mineral lubricating oil and a minoramount, sufficient to confer improved antioxidant andcorrosion-inhibiting properties on the composition, of the productobtainable by the process of claim 3.

18. A lubricant composition comprising a major amount of a minerallubricating oil and a minor amount, sufficient to confer improvedantioxidant and corrosion-inhibiting properties on the composition; ofthe product obtainable by the process ofc1aim'7. V

'19. A lubricant composition comprising a major amount of a minerallubricating oil anda minor amount; sufficient to confer improvedantioxidant and corrosion-inhibiting properties on the composition, ofthe product obtainable by the process of claim 10, 5 pq '1 V HERSCHEL G.SMITH.

TROY L. CANTRELL.

REFERENCES CITED 1 The following references are'of record i file of thispatent: 7

UNITED STATES PATENTS 1 1 e. f? Number Name" r Date r 2,167,867 BenningAug. 1, 1939 2,315,072 Nelson Mar. 30,- 1943 2,456,336 Smith Dec; 14,19518

1. THE PROCESS OF PREPARING AN IMPROVEMENT AGENT FOR MINERAL OILLUBRICANTS WHICH COMPRISES HEATING AN ESSENTIALLY PARAFFINIC BASELUBRICATING OIL WITH ANHYDROUS ALUMINUM CHLORIDE AT A TEMPERATURE OFFROM 150* TO 300* F., REMOVING ALUMINUM CHLORIDE FROM THE REACTIONPRODUCTS, AND REACTING SAID PRODUCT AND FROM 10 TO 75 PER CENT BY WEIGHTOF AN ALKYL PHOSPHATE HAVING AT LEAST 5 CARBON ATOMS IN THE ALKYL GROUPWITH PHOSPHORUS PENTASULFIDE AT AN ELEVATED TEMPERATURE NOT BELOW 300*F. AND NOT IN EXCESS OF THE MINIMUM CRACKING TEMPERATURE OF SAID PRODUCTTO INCORPORATE PHOSPHORUS AND SULFUR THEREIN.